Researchers at the University of Bath and University of Surrey have developed a way of introducing degradable bonds into thermoset polymers to make them more easily recyclable. An open-access paper on their work is published in the RSC journal Polymer Chemistry.

The team made a series of polymer gels with breakable bonds incorporated into different parts of the structure, and tested whether the properties changed after the gel was degraded and reformed.

They found that while all the gels could be degraded to some extent, gels with breakable bonds in the polymer chains retained their properties much better when reformed, compared with the polymers that were broken down via the cross-linked bonds.

Diagram showing locations of breakable bonds in thermoset polymers. Dawson et al.

The researchers hope this model system can be applied to other types of polymers, including adhesives, sealants and elastomers.

Thermosets are used widely in the commercial sector, in materials like resins and adhesives. Being able to make bonds reversible in these materials will increase their applications as well as making them more recyclable.

—Dr Maciek Kopeć,corresponding author

The researchers aim to create a general road map of the best locations for these breakable bonds, to understand better why some bonds break more easily than others, and plan to optimise the system using other commercially used polymers.

The work was funded by the Engineering and Physical Sciences Research Council (EPSRC).

Resources

• Frances Dawson, Touseef Kazmi, Peter J. Roth and Maciej Kopeć (2023) “Strands vs. crosslinks: topology-dependent degradation and regelation of polyacrylate networks synthesised by RAFT polymerisation” Polym. Chem. 14, 5166-5177 doi: 10.1039/D3PY01008B